Experimental Study of New Design 2.5kW Dead-End H2/02 PEM Fuel Cell Stack

Proton exchange membrane fuel cells (PEMFCs) with a dead-ended anode and cathode can obtain high hydrogen and oxygen utilization by a comparatively simple system. Nevertheless, the accumulation of the water in the anode and cathode channels can lead to a local fuel starvation, which degrades the performance and durability of PEMFCs. In this paper for the first time, a new design for a polymer electrolyte membrane (PEM) fuel-cell stack is presented which can achieve higher fuel utilization without using hydrogen and oxygen recirculation devices such as hydrogen pumps or ejectors, that consumes parasitic power and require additional control schemes. The basic concept of the proposed design is to divide the cells of a stack into several blocks by conducting the outlet gas of each stage to a separator and reentering to next stage, thereby constructing a multistage anode and cathode. In this design, a higher gaseous flow rate is maintained at the outlet of the cells, even under dead-end conditions, and this results in a reduction of purge-gas emissions by hindering the accumulation of liquid water in the cells. The result shows that the dead-end mode condition has the same performance as open-end mode.